There is a need for a simple, inexpensive, practical device to maintain the separable elements of an extension cord coupling against inadvertent separation. Frequently, the electrical cords of typical electrical equipment such as vacuum cleaners, hedge trimmers, or industrial machinery such as hand drills, extension lights and the like, must be coupled to an extension cord to reach their desired location of use. The inherent strength of the coupling brought about by the friction between the prongs of one plug on the first cord and their corresponding receptacle on the second cord generally will not withstand a force beyond the most moderate separating tension. In fact, this “unplugability” is a property built into common household cords.
One solution to this has been the use of “twist-lock” connectors. These find acceptance in heavy-duty industrial and theatrical settings. “Twist-lock” connectors employ special prongs and receptors which are not compatible with normal home or light industrial wall plugs or with the connectors on normal extension cords. Accordingly, this solution, while effective in an industrial setting, does not work in many more common applications.
Other devices have been developed for common applications of a power cord coupler. However, some of these devices place an undue amount of strain on the connection between the plugs, and, therefore, may damage the plugs or the electrical cords. Other devices which employ a clamp or similar apparatus may damage the electrical integrity of the conductors, the insulation, or the cover of the extension cord. Still other devices may waste a considerable amount of cord length due to the necessity of winding the cord around the device to transfer the strain from the cord to the device.
Thus, there is a need for a power cord coupling device that overcomes these and other disadvantages.